Ch1: Basic Pharm

Question 1

Dose-Response Curves (DRC)

Answer 1

Range of drug doses - should go from undetectable effect to a dose so high that increases in dose have no further effect, and a number of doses in between

X axis: dose
Y axis: effect

Question 2

ED50

Answer 2

Median effective dose - the dose that is effective in 50% of the individuals tested

Question 3

LD50

Answer 3

Median lethal dose - the dose that kills 50% of those tested

Question 4

Therapeutic Index/Ratio (TI)

Answer 4

Describes the safety of a drug

TI = LD50/ED50

Drug safety can also be described as a ratio of ED99 and LD1

Question 5

Potency

Answer 5

Differences in the ED50 of two drugs. Drug with lower ED50 is more potent.

Question 6

Effectiveness/efficacy

Answer 6

Differences in the maximum effect that the drugs will produce at any dose

Eg. aspirin and morphine are both painkillers, but aspirin at its most effective dose is not as effective as morphine

Question 7

Antagonism

Answer 7

Drug interactions - one drug diminishes the effect of another drug

DRC is shifted to the right (i.e., ED50 increases) by adding new drug

Question 8

Additive Effect

Answer 8

Effects of the combination = the sum of the expected effects of the two drugs alone

DRC is shifted to the left (i.e., ED50 decreases) by adding new drug

Question 9

Superadditive Effect/ Potentiation

Answer 9

Effects of the combination is greater than the expected sum of the two drugs

Eg. if one drug has no effect alone but increases the effect of a second drug

Question 10

Three processes of pharmacokinetics

Answer 10

1) Absorption: how a drug gets into blood
2) Distribution: where it goes into the body
3) Elimination: how the drug leaves the body

Question 11

Routes of administration

Answer 11

1) Parenteral
2) Inhalation
3) Oral administration
4) Transdermal administration

Question 12

Parenteral routes of administration

Answer 12

• Vehicle: dissolve drug in liquid (called vehicle) before it’s injected
• Subcutaneous: injected to form a bolus under the skin or tissue
• Intramuscular: injected into a muscle
• Intraperitoneal: injected into peritoneal cavity
• Intravaneous: injected into a vein, directly into bloodstream

Question 13

Absorption from parenteral sites

Answer 13

Fasted from ip injection, slowest from sc injection. Drug must pass through walls of capillaries.

Question 14

Inhalation routes of administrration

Answer 14

• Gases: breathed into the lungs

- Smoke & solids

Question 15

Distribution of drugs

Answer 15

• Lipid solubility: drug is slowly released from the fat into the blood over a long period of time
• Ion trapping: ionized molecules are not lipid soluble, so pKa of a drug can hasten or slow down its absorption
• Blood-brain barrier
• Active & passive transport across membranes
• Protein binding
• Placental barrier

Question 16

Elimination of drugs

Answer 16

• Metabolism
• Liver & kidneys
• First-pass metabolism: pass through liver before going anywhere else

Question 17

Factors that alter drug metabolism

Answer 17

• Stimulation of enzyme systems
• Depression of enzyme systems
• Age

Question 18

Therapeutic Window

Answer 18

Level of the drug maintained in the blood - the range between being too high of a level (eg. unwanted side effects, no increase in therapeutic effect) & falling below a certain level (eg. no therapeutic effect)